The present invention relates to electronic fuel injection, and more particularly to a method and system for injecting different quantities of fuel to individual cylinders so that cylinder-to-cylinder engine speed variations are minimized.
In conventional electronic fuel injection systems, engine speed and load parameters are continuously monitored and a single control variable is derived for metering the amount of fuel to be injected to all the injectors. One disadvantage of the prior art system resides in the fact that due to manufacturing tolerances and aging, the cross-sectional areas of the individual fuel injectors tend to differ from one another. Since the single control variable is used indiscriminately for all injectors, engine speed variations develop from one cylinder to the next with conventional fuel injection systems and will eventually cause engine instability. This is particularly severe when the engine is idled, making it difficult to regulate noxious emissions to within a narrow control range.